Display devices using a display panel such as a liquid crystal display panel, which does not emit light itself, typically incorporate an illumination device that illuminates the display panel from behind. Various types of light sources including cold cathode tubes and light emitting elements are used as the light source of such an illumination device. Examples of such light emitting elements include light emitting diodes (hereinafter referred to as “LEDs”), organic electroluminescence elements, inorganic electroluminescence elements, among which LEDs are used the most commonly today. The light sources of the illumination device disclosed in Patent Literature 1 are also LEDs.
In the illumination device disclosed in Patent Literature 1, as shown in FIG. 8, LEDs 122 are mounted on the mounting board 121, and further, lenses 124 each covering a corresponding one of the LEDs 122 are attached to the mounting board 121. The mounting board 121, the LED 122, and the lens 124 together form a light emitting module mj. The lenses 124 are each formed in a shape of a hemisphere dome with even thickness, and transmit light emitted from the LEDs 122 without significant refraction. Thus, if the LEDs 122 face upward as shown in FIG. 8, a large part of the light proceeds in a direction close to the vertical direction.